Convertible top and driving device for a convertible top

ABSTRACT

The invention relates to a convertible top for a convertible, comprising a front shell piece, a middle shell piece and a rear shell piece; said shell pieces, when in the closed state, being arranged as a roof over a passenger compartment of the convertible; said front shell piece being capable to be raised during a positively controlled opening operation such that it is moved over the middle shell piece; said rear shell piece being capable to be rotated into a folded-over position; the three shell pieces being designed such that they can jointly pivot counter to a direction of travel about a main bearing into a packaging position; wherein in said packaging position said front shell piece and said middle shell piece are oriented in the same direction over said rear shell piece, that is stored in the folded-over position. The invention further relates to a driving device for a convertible top, comprising a main bearing, a first link, a second link, an intermediate link, said intermediate link being coupled to said second link for activation purposes, a four-bar linkage, said four-bar linkage being coupled to said first link for activation purposes, a first bearing point, a driving cylinder, said driving cylinder being coupled with said main bearing at said first bearing point, and a push and pull rod, said push and pull rod being driven by said driving cylinder and being designed for a simultaneous action of force on the intermediate link and the four-bar linkage.

FIELD OF THE INVENTION

[0001] The present invention relates to a convertible top for aconvertible, comprising a front, a middle and a rear shell piece, saidshell pieces, when in the closed state, being arranged as a roof over apassenger compartment. The invention further relates to a driving devicefor a convertible top, comprising a main bearing, a first link, a secondlink and a driving cylinder.

DESCRIPTION OF THE PRIOR ART

[0002] Up to now collapsible tops known in practice are customarilydesigned in the form of folding tops, in which a flexible roof skin isstretched over a framework which is swung open out of the region of atrunk over a passenger compartment as far as a windshield. Collapsibletops of this type have proven problematical particularly in atransparent rear region of the collapsible top, i.e. in the region of arear window which is preferably of rigid design. Also, there aredrawbacks in winter for collapsible tops of this type due to a lack ofthermal insulation.

[0003] Furthermore, collapsible tops made of one or more rigid parts areknown. In the sphere of convertibles, collapsible tops of this type areconstructed in the form of convertible tops preferably made of two partsor shells. The size of the roof space which is to be covered by theconvertible top is not causing problems in this case because of therelatively small passenger cabin with just two proper seats. However,convertible tops are now also increasingly used outside convertibles,sport or leisure vehicles for conventional, four-seater vehicles orsaloons. In this case, construction of the convertible top in just twoparts is problematical because of the substantially larger passengercabin, particularly because in an open position the rigid shells of theconvertible top usually have to be accommodated behind the rear seatbench in the region of the trunk. Collapsible tops having an essentiallythree-part roof combination have proven successful here, it also beingpossible for this combination to comprise three rigid parts. Problemsarise in the kinematics for opening and closing convertible tops of thistype, with the result that they frequently have to be activated via morethan one drive. Furthermore, the usable space in the trunk isexcessively restricted by the packed collapsible top. Finally, accordingto the prior art the arrangement of the drive and the further elementsof the drive on or in the convertible top is also problematical, so thatparts thereof have even been arranged so that they can be seen from theoutside. Among other things, this gives rise to aerodynamic problems andalso stability problems.

[0004] German laid open publication DE 19642 154 A1 describes a motorvehicle having a retractable roof which is subdivided into a front,middle and a rear subpiece, it being possible for the front subpiece tobe folded in the opposite direction to the middle subpiece and for themiddle subpiece to be shifted in the same direction as the rearsubpiece. The driving device of the retractable roof comprises a mainbearing having two links which are secured pivotably to the mainbearing, one of the links being configured such that it can be drivenabout its pivot axis.

SUMMARY OF THE INVENTION

[0005] It is an object of the invention to provide a convertible tophaving an improved kinematic arrangement.

[0006] It is a further object of the invention to provide a drivingdevice for a convertible top, with which a convertible top can be drivenreliably and in a space-optimized manner.

[0007] It is another object of the invention to provide a convertiblehaving a convertible top according to the invention and a driving deviceaccording to the invention for a convertible top.

[0008] These and further objects are achieved by the invention.

[0009] A convertible top according to the invention comprises a frontshell piece, a middle shell piece and a rear shell piece; said shellpieces, when in the closed state, being arranged as a roof over apassenger compartment of the convertible; said front shell piece beingcapable to be raised during a positively controlled opening operationsuch that it is moved over the middle shell piece; said rear shell piecebeing capable to be rotated into a folded-over position; the three shellpieces being designed such that they can jointly pivot counter to adirection of travel about a main bearing into a packaging position;wherein in said packaging position said front shell piece and saidmiddle shell piece are oriented in the same direction over said rearshell piece, that is stored in the folded-over position.

[0010] A driving device for a convertible top according to the inventioncomprises a main bearing, a first link, a second link, an intermediatelink, said intermediate link being coupled to said second link foractivation purposes, a four-bar linkage, said four-bar linkage beingcoupled to said first link for activation purposes, a first bearingpoint, a driving cylinder, said driving cylinder being coupled with saidmain bearing at said first bearing point, and a push and pull rod, saidpush and pull rod being driven by said driving cylinder and beingdesigned for a simultaneous action of force on the intermediate link andthe four-bar linkage.

[0011] A convertible according to the invention includes a convertibletop and a driving device for said convertible top, said convertible topcomprising a front shell piece, a middle shell piece and a rear shellpiece, said shell pieces, when in the closed state, being arranged as aroof over a passenger compartment of the convertible, said front shellpiece being capable to be raised during a positively controlled openingoperation such that it is moved over the middle shell piece, said rearshell piece being capable to be rotated into a folded-over position, thethree shell pieces being designed such that they can jointly pivotcounter to a direction of travel about a main bearing into a packagingposition, wherein in said packaging position said front shell piece andsaid middle shell piece are oriented in the same direction over saidrear shell piece, that is stored in the folded-over position, and saiddriving device comprising a main bearing, a first link, a second link,an intermediate link, said intermediate link being coupled to saidsecond link for activation purposes, a four-bar linkage, said four-barlinkage being coupled to said first link for activation purposes, afirst bearing point, a driving cylinder, said driving cylinder beingcoupled with said main bearing at said first bearing point, and a pushand pull rod, said push and pull rod being driven by said drivingcylinder and being designed for a simultaneous action of force on theintermediate link and the four-bar linkage.

[0012] The convertible top according to the invention comprises a frontshell piece, a middle shell piece and a rear shell piece which, when inthe closed state, is arranged as a roof over a passenger compartment ofa vehicle. It is thereby advantageously possible even to cover largeand, in particular, 4-seater vehicles with the convertible top. Duringthe folding process, a positive control of the convertible top isoperational in such a manner that first of all the front shell piece israised and displaced over the middle shell piece. By this means, thefront shell piece and the middle shell piece are placed one above theother in the same direction and are transferred into a very compactpacking position over the rear shell piece, which can be rotated into afolded-over position. This packing position can be reached as a secondend position of a convertible top during the course of a positivecontrol which is described. The packed convertible top is arranged in aknown manner behind the rear bench in the region of the trunk of thevehicle.

[0013] The type and manner of the above-described positive control forthe movement sequence during the opening and closing means that theconvertible top is therefore able on the whole to form a very compactpacking position. In a development, the positive control is broughtabout by a chain of four-bar mechanisms which are coupled to oneanother, in which chain all of the parts of the drive are arrangedsecurely between the shell parts in the packed end position. In thisarrangement, the convertible top can also be activated by just one driveand restricts the otherwise freely usable space in the trunk to just arelatively small extent. Furthermore, none of the parts of the drive ofa convertible top forming the basis of the invention are arranged sothat they can be seen from the outside, and so aerodynamic problems donot arise.

[0014] The above-described positive control means that the convertibletop is suitable for use with rigid shell parts and also generally foruse in partially or completely flexible roof skins. Mixtures of thesetwo forms are also possible, with the result that, in particular, thesupporting lengths, which are known from flexible convertible tops, arecoupled in a simple manner to a roof skin and are intended forincreasing the stability of the convertible top, are replaced by a partwhich is widened in a shell-like manner and is reinforced. In adevelopment, such a part can be designed for the direct integration of aroll bar or of a plurality of supporting bars of this type, and can becoupled to the flexible roof skin. Furthermore, in a convertible topaccording to the invention rigid shell parts, for example a rear window,can also be integrated in a simple manner in a roof skin itself, wherethe roof skin is otherwise flexible.

[0015] The driving device according to the invention for a convertibletop enables two links, which are connected to a further positive-controlmeans of the convertible top, each to be able to pass through differentmovements by each having their own coupling in the region of a mainbearing, it being advantageous for them both to be driven by the sameaction of force.

[0016] In a preferred embodiment, the input of force into the drive ofthe convertible top takes place by a hydraulic or pneumatic drivingcylinder, a rack or the like. In this case, the construction of thedrive is adjusted about a main bearing of a convertible top in such amanner that the input of force is optimized. The effect thereforeachieved in particular is that, at the beginning and end of the movementsequence in each direction, the movement when subjected to a high forceproceeds slowly and therefore safely and gently for the elements. Forthis purpose, a four-bar linkage is advantageously provided in theregion of the drive, said four-bar linkage bringing about a change tothe effective lever arms, which change is matched to the particularstate of the convertible top, during the transmission of force. Anadditional control of the force profile can take place via the input offorce.

[0017] In a configuration according to the invention of the drivingdevice, an intermediate link is advantageously provided in the couplingof the second link of the convertible top. The effect achieved by thisis that the second link of the convertible top not only executes arotational movement, but also a combined translatory movement withregard to a fixed bearing point of the driving device. By suitablyconfiguring this coupling, jamming of the entire linkage mechanism ofthe convertible top can effectively be avoided.

[0018] Further advantageous designs and developments of a driving deviceaccording to the invention and of a convertible top are thesubject-matter of dependent claims and of the following description of apreferred embodiment of the invention.

[0019] A preferred embodiment of a convertible top according to theinvention and of a driving device according to the invention for aconvertible top is explained in greater detail below with reference tothe associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 shows a schematic side view of a preferred exemplaryembodiment of a convertible top together with a driving device accordingto the invention in the closed state on a vehicle;

[0021]FIG. 2 shows the convertible top from FIG. 1 in a first step ofthe opening movement;

[0022]FIG. 3 shows the convertible top from FIG. 1 in a second step ofthe opening movement;

[0023]FIG. 4 shows the convertible top from FIG. 1 in an opened endposition; FIG. 5 shows an enlarged illustration of the driving device ofthe convertible top from FIG. 1;

[0024]FIG. 6 shows a schematic illustration of the links and hingepoints in the position of FIG. 5;

[0025]FIG. 7 shows an enlarged illustration of the driving device in thefirst opening position from FIG. 2;

[0026]FIG. 8 shows a schematic illustration of the links and hingepoints in the position of FIG. 7;

[0027]FIG. 9 shows an enlarged illustration of the driving device in thesecond opening position from FIG. 3;

[0028]FIG. 10 shows a schematic illustration of the links and hingepoints in the position of FIG. 9;

[0029]FIG. 11 shows an enlarged illustration of the driving device inthe open end position from FIG. 4;

[0030]FIG. 12 shows a schematic illustration of the links and hingepoints in the position of FIG. 11.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0031] In FIG. 1, a vehicle 1 having a convertible top 2 is illustratedin a side view. In a manner visible from the outside, the convertibletop 2 comprises a front shell piece 4, a middle shell piece 5 and a rearshell piece 6 which, when in the closed state, are arranged as a roofhaving a uniform outer contour over a passenger compartment 9. The roofextends for this purpose from a region 10 of a trunk 11 as far as aframe of a windshield 12.

[0032] A mechanism of bars in the form of a chain 14 is provided belowthe shell pieces 4, 5, 6. The chain 14 can therefore not be seen fromthe outside. The mechanism of bars has the task of ensuring the sequenceof operation of a positive-control means in a form as described below.For this purpose, the mechanism of bars is designed in the form of thechain 14 and extends from two bearing points A, B of a main bearing 16in the region 10 of the trunk 11 of the vehicle 1 virtually as far as aroof point 17, which forms the region of contact of the front shellpiece 4 with the frame of the windshield 12. Arranged in the region ofthe main bearing 16 is a driving device which is also illustrated anddescribed in detail below in enlarged illustrations. Starting from thisdriving device a force is transmitted via the chain 14 to all of theshell pieces 4, 5, 6. The construction of the chain 14 from coupledfour-bar linkages 18, 19, 24, 30 produces a certain kinematicarrangement during the opening and closing of the convertible top 2,which arrangement is now described by an illustration of a first step ofthe opening movement with reference to FIG. 2 and of a second step ofthe opening movement with reference to FIG. 3 using the movement arrowsP1, P2, P3 and P4.

[0033] The front shell piece 4 is raised along the arrow P1 anddisplaced along the arrow P2 counter to the direction of travel. Bothmovements immediately start with a rotational movement, caused at themain bearing 16 by the driving device, along the arrow P3. In theirextent, the three movements differ in strength, so that first theraising along P1 is dominant. By this means, the front shell piece 4 canbe raised over the middle shell piece 5 and then moved over the middleshell piece 5. This movement is essentially controlled by the four-barlinkages 18, 19 below the front shell piece 4, the front shell piece 4being fastened to a four-bar linkage 19 which is formed out as aparallelogram mechanism and which is activated via a small four-barlinkage 18 mounted upstream of it. The dimensioning of the parallelogrammechanism 19 essentially determines, by means of the length of links 20,21, the maximum height that the front shell piece 4 can be raised overthe middle shell piece 5, with the result that these parts cannot comeinto undesirable contact and therefore be damaged during opening orclosing.

[0034] However, this type of opening movement also has furtheradvantages: the roof tip 17 is generally fixed or secured in a knownmanner by means of a fastener (not illustrated here in further detail)or in a holding device in the region of the windshield 12. The describedcommencement of the opening movement is matched in a particular mannerto a release operation of the roof point 17 from the fastener orplurality of fasteners. Furthermore, raising prior to the commencementof the actual displacement movement protects seals situated between theparts to a very high extent, since only small shearing forces thereforeoccur at the seals. The illustrated opening movement is therefore alsolargely free of wear concerning the seals in the intermediate regions ofthe abovementioned parts.

[0035] In contrast, in this first phase of the opening movement there isno very complex relative movement between the middle shell piece 5 andthe rear shell piece 6. Deviating from the present exemplary embodiment,these parts may be coupled to one another via a hinge point 22. Then,during the further course of the opening movement, they execute a purelyrotational movement about the hinge point 22. The movement according tothe present exemplary embodiment of FIG. 2 and FIG. 3 is characterizedby the combining of a rotational movement with a translatory movement,so that more than just the formation of a gap between the middle shellpiece 5 and the rear shell piece 6 can be seen. In each case, the middleshell piece 5 has also been clearly moved along the arrow P2 from itsinitial position. A comparison of the illustrations of FIG. 1 and FIG. 3shows that the rear shell piece 6 has also been rotated along the arrowP3 from its initial position toward an oppositely directed storageposition in the region of the trunk 11.

[0036]FIG. 3 therefore illustrates a virtually maximum height deflectionof the convertible top 2 during the opening operation. The movementalong the arrow P1 has therefore essentially come to an end here.Dominant in this state is the displacement of the front shell piece 4and of the middle shell piece 5 along the arrow P2 together with thebeginning of a lowering of these parts along arrow P4 into the region ofthe trunk 11. The rotation of the rear shell piece 6 has already beenapproximately half finished here.

[0037] In the illustration according to FIG. 3, the construction of thechain 14 with the individual parts can be seen particularly well. Theparallelogram mechanism 19 has already exceeded the vertex of itsopening and is merging from a rectangle via the illustratedparallelogram into a second end position. The same applies to theconnected four-bar linkage 18 via which the parallelogram mechanism 19is essentially activated. On the other side of the four-bar linkage 18,the chain 14 is continued by a further four-bar linkage 24 whosevirtually parallel legs 25 and the leg piece of the first link 26 arevery short, so that the substantially longer links 27, 28 seem to liedirectly one above the other. The links 27, 28 each have a plurality ofhinge points, so that they are also part of a plurality of four-barlinkages 18, 19, 24 and 30. They therefore cover a very wide region overthe passenger compartment 9 from the hinge point 22 in the vicinity ofthe rear shell part 6 as far as the front shell piece 4 in the region ofthe roof point 17. In this arrangement, the links 27, 28 are designed sothat they are bent in order to bring about the activation of theindividual four-bar linkages 18, 19, 24 in the desired form. A furtherpositive effect of the illustrated formation of the links 27, 28 inparticular is the production, in the closed position according to FIG.1, of a profile extending overall in a curved shape and being ideallymatched to the profile of the convertible top 2.

[0038] The chain 14, for example even as a whole, can therefore bereadily integrated in the inner panel or in the roof lining. Optionsinclude, for example, channels in the roof lining into which the linksof the chain 14, which links are in each case arranged toward the sideof the passenger compartment 9, can be introduced in the closed positionof the convertible top 2. Lips or bristle strips arranged on one side orboth sides of channels of this type can close the channels in the closedend position. Elements of this type can be matched in a known manner indesign and also color to the particular interior of the vehicle 1.Alternatively, two chains 14 on outer longitudinal edges of theconvertible top 2 may, for example, be arranged in recesses. Theserecesses may be part of the door frames.

[0039] In the closed end position according to FIG. 1, a four-barlinkage 30 is folded together almost as tightly as the four-bar linkage24. With the main bearing 16 as the base point, the four-bar linkage 30forms the fixed connection of the chain 14 to the vehicle 1.Furthermore, a driving device in the region of the main bearing 16 actson the four-bar linkage 30, as is also described below. In order tooptimize their function and position in both end positions, a first link26 and a second link 32 of the four-bar linkage 30 are also designedsuch that they are bent.

[0040] In the illustrated and preferred embodiment of the invention,each part of the total of four four-bar linkages 18, 19, 24, 30 isdesigned in the form of a link. An increase in the mechanical rigidityof the chain 14 is therefore brought about, since recourse is notnecessarily made to the rigidity of the shell pieces 4, 5, 6. This alsoresults in simple assembly of the chain 14 with the shell pieces 4, 5,6, for example via tabs with screw connections or welding connections ora bonding connection or the like, as indicated in a region of contact aof the four-bar linkage 30 on the first link 26 with the rear shellpiece 6 and a region of contact b of the parallelogram mechanism 19 withthe front shell piece 4.

[0041] Furthermore, in the chain 14 which is illustrated, the hingepoints are predominantly designed in a known and therefore very reliabletechnique as swivel joints. In comparison with sliding bearings, swiveljoints have the advantage that they can be provided in a simple manner,for example by provision of sliding sleeves or the like, withpermanently good and maintenance-free lubrication. Sleeves, disks orsimilar elements having a Teflon coating are preferably used here in theswivel joints.

[0042] However, in certain applications sliding bearings can also beused. However, the use of sliding bearings instead of swivel joints mayalso cause problems to arise in particular because of a free combinationof translatory and rotational movement inter alia in the point ofconnection or transition between these types of movement, sinceundefined positions of the mechanism may arise during or at the end ofthe largely arbitrary movement sequences. However, the use of slidingbearings is only optional, since a convertible top 2 according to theinvention in principle also operates correctly and reliably without theuse thereof.

[0043] In a final step of the opening movement, the convertible top 2 islowered, in the transition from FIG. 3 to FIG. 4, in a movement with asubstantial component in the direction of arrow P4 into the region 10 ofthe trunk 11 of the vehicle 1 in such a manner that the front shellpiece 4 is arranged over the middle shell piece 5 in the same directionand the two parts 4, 5 are arranged over the rear shell piece 6. In theprocess, the rear shell piece 6 has been rotated along the arrow P3 intoa position folded over with respect to its initial position. Theabovementioned parts 4, 5, 6 are situated in such a manner that thelinks 27, 28, as some of the longest parts of the convertible top 2, arearranged between the front shell piece 4 and the middle shell piece 5,on the one hand, and the folded-over, rear shell piece 6. In this form,in spite of the protection by means of the shell parts, the links 27, 28do not produce, together with the first link 26, a substantiallengthening of the convertible top 2 in the axis of the maximumextension of its packing position.

[0044] An essential feature of this arrangement of the parts of theconvertible top 2 is that the shell pieces 4, 5, 6 have not even beenplaced one inside another. Rather, the parts of the illustratedembodiment rest one on another, see FIG. 4. By this means, no particularrestrictions with regard to the shape and/or size of a particular shellpiece are applied. Therefore, virtually any roof shape can be realizedby means of a convertible top according to the invention. Nesting theshell parts 4, 5, 6 in one another taking into consideration theinevitably resultant limitations can further increase the packingdensity of the convertible top in its packing position. The spacerequired overall in the region 10 of the trunk 11 of the vehicle 1 cantherefore be reduced further.

[0045] An essential element of this embodiment is a special drivingdevice which is arranged in the region of the main bearing 16 and isdescribed in respect of its function and its construction with referenceto FIGS. 5 to 12. The driving device comprises a hydraulic drivingcylinder 36 which is mounted, in a manner such that it can pivot on oneside, on a bearing point C in the region of the main bearing 16. In aknown manner, the hydraulic driving cylinder 36 may, for example, bearranged between the fixed bearing point C and a further bearing point,the second bearing point being situated in a central region of thesecond link 32. In contrast, the hydraulic driving cylinder 36 accordingto the present embodiment is coupled in a novel manner to the chain 14so as, among other things, to improve the driving characteristics of thedriving device. For this purpose, the four-bar linkage 30 is matched tothe driving device by a lengthening of the bearing-side, bent ends ofthe first link 26 and of the second link 32. The lengthened portion ofthe second link 32 is designed as a double lever 35 which can be pivotedabout the bearing point B of the main bearing 16.

[0046]FIG. 5 shows an enlarged illustration of the region about thedriving device of a convertible top 2 according to the invention in theclosed position of FIG. 1. The basic construction of the driving devicetogether with its component parts can therefore be seen precisely. Thedriving cylinder 36 has an extended piston rod 38 which is connected viaan end-side hinge point 39 to a push and pull rod 40. The push and pullrod 40 is designed for the simultaneous driving of a link system 42 andof a four-bar linkage 43. For this purpose, the push and pull rod 40 isprovided with a first hinge point 46, a second hinge point 47 and athird hinge point 48. The four-bar linkage 43 is designed as a crossjoint, i.e. two links 55, 57 of this sub-mechanism, which is not capableof revolving, cross over each other in every possible position.

[0047] The construction of the four-bar linkage 43 in detail is asfollows: at the third hinge point 48 the push and pull rod 40 isconnected to a first bent link 57 which is coupled via a fifth hingepoint 45 to an end of the double lever 35. On the other side of thefixed bearing point B, the double lever 35 is connected via a fourthhinge point 59 to a second bent link 55. The link 55 is connected againto the push and pull rod 40 via the second hinge point 47. Thiscompletes the cross joint 43.

[0048] The construction of the link system 42 belonging to the secondlink 32 of the convertible top in detail is as follows: an intermediatelink 50 is connected, in a manner such that it can pivot at the fixedbearing point A, to the main bearing 16. At the other end of theintermediate link 50, the second link 32 and the intermediate link 50are connected pivotably in the hinge point 51. The push and pull rod 40is connected to the intermediate link 50 in a first hinge point 46 whichlies between the hinge point 51 and the bearing point A. In thisarrangement, the intermediate link 50 is shaped because of structuralconditions in such a manner that the first hinge point 46 lies in adifferent plane than the hinge point 51 and the bearing point A.

[0049] The above-described, basic construction of the driving device isreproduced in FIG. 6 in the form of a schematized illustration of thelinks and hinge points involved in the position as illustrated in FIG.5. For the purpose of comprehension it should be taken intoconsideration here that the linear pieces drawn in concern lines offorce, i.e. furthermore concern links or levers and not bars in thepurely mechanical sense. Links or levers can also transmit forces whichdo not act in the direction of their axis. Bars, in contrast, can onlytransmit forces along their axis.

[0050] In order to describe the advantageous effect of this constructionusing the cross joint 43, there has furthermore been entered in FIG. 6an arrow P which reproduces the direction of the force exerted on thearrangement by the driving cylinder 36 via the push and pull rod 40.Taking into consideration the virtually perpendicular position of thepush and pull rod 40 with respect to the double lever 35 with a leverarm h, this force produces a torque M about the bearing point B. Inreaction to this torque M the first link 26 is then rotated in thedirection of the arrow drawn in and the following mechanism of barscomprising coupled four-bar linkages is driven for the purpose ofopening the convertible top 2 (FIG. 1).

[0051] The change in the position of the individual elements of thedriving device from the closed position according to FIG. 5 is shownbelow in enlarged illustrations of the driving region as intermediatepositions in FIG. 7 and FIG. 9 and as an open end position in FIG. 11.Respectively associated therewith FIGS. 8, 10 and 12 reproduce aschematized illustration of the links and hinge points in particulartaking into consideration the lever ratios at the cross joint 43 in asimilar manner to the illustration from FIG. 6. In a comparison of FIGS.10 and 12, a considerable change in the magnitudes of the respectivelever arms h at the cross joint 43 can be ascertained. With the sameforce exerted by the magnitude P, because of these changes in therespective effective lengths of the lever arms, torques M differinggreatly in size are therefore produced at the beginning and at the endof the opening movement and in an intermediate position. The lever armsh are therefore at a respectively maximum size in the extreme positionsor end positions, while they are small in a central region of themovement with a relatively large speed in the described system. Thetorque is therefore particularly large especially at the beginning ofthe movement from a static or inoperative extreme position, where alarge driving torque is also used for starting the movement. There istherefore a force and speed distribution which is matched to the actualrequirements during opening and closing of a convertible roof and istherefore substantially improved with respect to known systems duringthe movement sequence. This distribution is advantageously producedwithout a further controlling intervention on the driving cylinder 36itself. An additional controlling intervention can be made at the end ofthe respectively finishing movement, for example shortly before anextreme or end position which is aimed at is reached, in order to assistin a gently expiring movement. For this purpose, the force output by thedriving cylinder 36, in particular, can be controlled.

[0052] Via the intermediate link 50 which can be moved by the push andpull rod 40, the link system 42 has the effect that the second link 32of the convertible top does not execute a purely rotational movementabout the fixed bearing point A, but, further caused by its coupling tothe further links of the chain 14, rather executes a combination of arotating movement about the bearing point A and a translatory movementrelative to the bearing point A. It can therefore be ensured, bysuitable selection of the length of the intermediate link 50 and theconnection to the push and pull rod 40 in the first hinge point 46, thatthe chain 14 of the convertible top can be driven by the driving deviceaccording to the invention without jamming.

[0053] A stop arm 60 is secured to the second link 32 in the region ofthe bearing point B and moves together with the second link. Alimitation of the movement of the driving device is provided by means ofa stop 61 on which the stop arm 60 acts in the one end position of thedriving device. This limitation can be adjusted precisely via adjustingscrews in order to take the tolerances of the entire mechanism intoconsideration. A second adjustable stop 62 is provided on the mainbearing and the second link 32 acts against it in the correspondingother end position of the driving device.

[0054] Compared with drives from the prior art, with a driving devicedescribed comparatively extreme end positions can be reached, in whichthe activated first and second links 26, 32 are rotated even aboutangles of rotation of more than 180° about the bearing points A, Bduring the transfer from one end position into the other end position.It is therefore even possible, if required, to realize drives with firstand second links 26, 32 which cross over in the region of the fixedbearings A, B.

[0055] It should also be pointed out here that the driving cylinder 36has only moved through an angle of a few degrees during the entiremovement from the closed to the open position. Therefore, in addition tothe temporal distribution of the driving force there has also been asubstantial improvement in the spatial input of the force within thedriving system as compared with the conventional driving solutiondescribed at the beginning. An above-described driving device thereforerequires substantially less free space than comparable arrangements. Asa result, the described driving device can be arranged in a very compactform and in a stable and well-protected manner in the region of theC-pillar of a motor vehicle. An advantageous distribution of the drivingforce to the main pillar and main link has also been made possible.

[0056] The above-described embodiment of a convertible top 2 accordingto the invention relates only to a three-part convertible top with rigidshell parts. However, this embodiment can also be used with slightadaptation for folding tops with a completely or partially flexible roofskin. A folding top with a partially flexible roof skin may, forexample, contain a rigid rear window or other or further rigid parts.Further links may be arranged on the chain 14 in a known manner, saidfurther links being connected to the flexible roof skin for shapingpurposes. By means of the positive control in a convertible top 2according to the invention, a convertible top 2 of this type having apartially flexible roof skin is also moved reliably and safely by thekinematic arrangement with low dynamic stressing of sensitive parts. Itis also possible within this framework to form one of the shell pieces4, 5, 6 as a roll bar between two chains 14 and to couple it to aflexible roof skin. In a convertible top according to the invention,these bars do not have to be directly activated; a simple couplingsuffices here because of the influence of the flexible roof skin, as isknown from the prior art from the sphere of flexible convertible tops.However, the integration of a roll bar in the convertible top inexchange for the known links, which are configured more just for theshaping of the convertible top, is novel.

What is claimed is:
 1. A convertible top for a convertible, comprising afront shell piece, a middle shell piece and a rear shell piece, saidshell pieces, when in the closed state, being arranged as a roof over apassenger compartment of the convertible, said front shell piece beingcapable to be raised during a positively controlled opening operationsuch that it is moved over the middle shell piece, said rear shell piecebeing capable to be rotated into a folded-over position, the three shellpieces being designed such that they can jointly pivot counter to adirection of travel about a main bearing into a packaging position,wherein in said packaging position said front shell piece and saidmiddle shell piece are oriented in the same direction over said rearshell piece, that is stored in the folded-over position.
 2. Theconvertible top as claimed in claim 1 , wherein a chain of coupledfour-bar linkages is provided for driving the convertible top.
 3. Theconvertible top as claimed in claim 2 , wherein one of the four-barlinkages is designed as a parallelogram mechanism.
 4. The convertibletop as claimed in claim 2 , wherein the chain comprises four four-barlinkages which are coupled to one another.
 5. The convertible top asclaimed in claim 2 , wherein the chain comprises seven links.
 6. Theconvertible top as claimed in claim 5 , wherein the links of the chainare designed such that they are partially bent.
 7. The convertible topas claimed in claim 5 , wherein the links are connected to one anothervia hinge points.
 8. The convertible top as claimed in claim 7 , whereinthe hinge points are designed as swivel joints.
 9. The convertible topas claimed in claim 8 , wherein sleeves, disks or similar elementshaving a Teflon coating are used in the swivel joints.
 10. Theconvertible top as claimed in claim 7 , wherein the hinge pointscomprise sliding sleeves for maintenance-free lubrication.
 11. Theconvertible top as claimed in claim 2 , wherein the chain is integratedin an inner panel or in a roof lining.
 12. The convertible top asclaimed in claim 2 , wherein the convertible top comprises two chainswhich are arranged on the outside, as seen from a central axis of theconvertible top.
 13. The convertible top as claimed in claim 2 ,wherein, in the closed state of the convertible top, the chain isarranged on outer longitudinal edges of the convertible top in recessesin an inner panel.
 14. The convertible top as claimed in claim 13 ,wherein the recesses can be covered by lips and brush strips arranged onsides of the recesses.
 15. The convertible top as claimed in claim 13 ,wherein the recesses are situated in the region of door frames.
 16. Theconvertible top as claimed in claim 1 , wherein a roof tip of theconvertible top can be secured in the region of a windshield by afastener or in a holding device.
 17. The convertible top as claimed inclaim 1 , wherein the shell pieces are arranged nested in one another ina packing position so as to increase the packing density.
 18. Theconvertible top as claimed in claim 1 , wherein the convertible topfurther comprises a partially or completely flexible roof skin.
 19. Theconvertible top as claimed in claim 18 , wherein supporting links whichare coupled to the roof skin and are intended for increasing thestability of the convertible top are formed by parts which are widenedin a shell-like manner and are reinforced.
 20. The convertible top asclaimed in claim 18 , wherein the shell pieces are designed as supportsand are coupled to the flexible roof skin.
 21. The convertible top asclaimed in claim 1 , wherein the shell pieces are designed for thedirect integration of a roll bar.
 22. The convertible top as claimed inclaim 18 , wherein a rear window, is connected to the flexible roofskin.
 23. A driving device for a convertible top, comprising a mainbearing; a first link; a second link; an intermediate link, saidintermediate link being coupled to said second link for activationpurposes; a four-bar linkage, said four-bar linkage being coupled tosaid first link for activation purposes; a first bearing point; adriving cylinder, said driving cylinder being coupled with said mainbearing at said first bearing point; and a push and pull rod, said pushand pull rod being driven by said driving cylinder and being designedfor a simultaneous action of force on the intermediate link and thefour-bar linkage.
 24. The driving device as claimed in claim 23 ,wherein the driving cylinder can be driven hydraulically, and whereinthe driving cylinder is mounted on the first bearing point in the regionof the main bearing in a manner such that it can pivot on one side. 25.The driving device as claimed in claim 23 , wherein the first link isdesigned as a double lever, and wherein the link can be pivoted about asecond bearing point of the main bearing.
 26. The driving device asclaimed in claim 23 , wherein the intermediate link is mounted at oneend in a manner such that it can pivot in a joint on the second link,and is mounted at the other end in a manner such that it can pivot abouta third bearing point of the main bearing.
 27. The driving device asclaimed in claim 23 , wherein the driving cylinder has an extendedpiston rod which is connected via an end-side hinge point to the pushand pull rod, the push and pull rod being connected to the intermediatelink and the four-bar linkage.
 28. The driving device as claimed inclaim 27 , wherein the push and pull rod is provided with a first, asecond and a third hinge point.
 29. The driving device as claimed inclaim 23 , wherein the four-bar linkage is designed as a cross jointwhich forms a sub-mechanism which is not capable of revolving.
 30. Thedriving device as claimed in claim 28 , wherein, in order to form thefour-bar linkage, the pull and push rod is connected at the second hingepoint to a first bent link, which first bent link is coupled via afourth hinge point to an end of the double lever, and on the other sideof the second bearing point the double lever is connected via a fifthhinge point to a second bent link, which is coupled via the third hingepoint to the push and pull rod.
 31. The driving device as claimed inclaim 28 , wherein the push and pull rod is connected at the first hingepoint to the intermediate link.
 32. The driving device as claimed inclaim 31 , wherein the first hinge point is arranged on the intermediatelink between the joint and the third bearing point.
 33. The drivingdevice as claimed in claim 23 , wherein means for controlling the forceoutput of the driving cylinder are provided.
 34. The driving deviceaccording to claim 23 , wherein the driving device is designed forachieving angles of rotation of the first and the second link of morethan 180° during the transfer from one end position into another endposition.
 35. The driving device as claimed in claim 24 , wherein thedriving cylinder can be moved through an angle of a few degrees aboutthe first bearing point during an entire movement process.
 36. Thedriving device as claimed in claim 23 , wherein a stop arm is secured tothe first link or to the second link, and a stop is provided on the mainbearing in such a manner that the stop arm and stop engage against eachother in an end position of the driving device.
 37. A convertibleincluding a convertible top and a driving device for said convertibletop, said convertible top comprising a front shell piece, a middle shellpiece and a rear shell piece, said shell pieces, when in the closedstate, being arranged as a roof over a passenger compartment of theconvertible, said front shell piece being capable to be raised during apositively controlled opening operation such that it is moved over themiddle shell piece, said rear shell piece being capable to be rotatedinto a folded-over position, the three shell pieces being designed suchthat they can jointly pivot counter to a direction of travel about amain bearing into a packaging position, wherein in said packagingposition said front shell piece and said middle shell piece are orientedin the same direction over said rear shell piece, that is stored in thefolded-over position, and said driving device comprising a main bearing;a first link; a second link; an intermediate link, said intermediatelink being coupled to said second link for activation purposes; afour-bar linkage, said four-bar linkage being coupled to said first linkfor activation purposes; a first bearing point; a driving cylinder, saiddriving cylinder being coupled with said main bearing at said firstbearing point; and a push and pull rod, said push and pull rod beingdriven by said driving cylinder and being designed for a simultaneousaction of force on the intermediate link and the four-bar linkage.